#earthscopetransportablearray — Public Fediverse posts

Seismic Velocity Modeling and the Denali Fault, Alaska

The NSF EarthScope Transportable Array is a network of seismic stations that were migrated across the US in 2004 to 2015 to collect data to allow geoscientists to map the structure of the earth below North America. Seismic waves from earthquakes travel through the earth at different velocities depending on the material they travel through. Seismic velocity modeling uses this information to map the depth and thickness of subsurface layers.

Alaska is well known for its large earthquakes along the subduction zone below its southern border, but Alaska also has strike-slip style faulting in its interior, including the Denali fault. In the study linked below, scientists have used the data gathered from the Alaska deployment of the Transportable Array to determine that the Denali Fault is where it is because of an increase in strength on the northern side of the fault that goes all the way through the upper plate; that the fault at the surface formed and stayed at the edge of this thicker, stronger lithosphere.

“There has been this controversy that faults in the shallower brittle crust wouldn't connect to structures in the deepest part of the plate, but here we show that they do, and this could mean a variety of things. For example, it means that we could expect earthquakes occurring deeper than previously thought for strike-slip faults such as the Denali fault, and that plate motions could occur on clear boundaries that extend from shallow faults all the way to the base of the plate."
~ Isabella Gama, lead author

Variations in Lithospheric Thickness Across the Denali Fault and in Northern Alaska, Isabella Gama, et. al.: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022GL101256

#SeismicVelocityModeling #DenaliFault #Alaska #EarthScopeTransportableArray #seismology #geology #science @geology